Colour ramp in 2.8 only picks the last colour stop.
It's probably because Blender 2.80 is in beta.
However, there is nothing wrong with the color ramp node; it is actually the sky texture node returning solid white. Until sky texture is implemented, you can render out a full spherical HDRi (512x256 res 16bit .exr recommended) with 2.79 and use that in place of the sky texture.